Setting
up FK - first, let me explain some
basic stuff about rigging a character.
The goal here is to create a rig that'll
allow the animator to create a very
broad range of expressive motions,
while using very simple and well-laid
out controls. The animator should
have everything setup, so his work
will flow steadily, quickly and, why
not, pleasantly. I think I have been
able to build a pretty decent rig,
packed with lots of power and lots
of ease. Nuff said, let's get to it.
We'll
first set up FK-animated hierarchies,
since it'll be easier to do. Let's
start with the spine.
SPINE ROTATORS
Remember
my ol' rotator helper objects? (now
available in the scripts section).
They're back! In new orange flavor!
And you'll need some of them for your
character (or any other helper object).
Ok. I've set two of them at the root
of the spine chain. One is orange,
and one is red. One will control the
hips rotation (red), and the other
one will controls the spine's initial
rotation. I also use three more, set
at different levels of the chain (every
two bones). Now, link the bone before
each rotator object to the rotator,
and the rotator to the following bone
(in an upwards direction). The thing
is to 'insert' the rotators into the
chain. The first rotator should be
the parent of the whole chain. The
others should be inserted into the
chain at their proper levels. Just
likn them to the bone below them,
and link the bone above to them. I
named mines something like 'Rotator_spinelow',
'Rotator_spinemid', and 'Rotator_spineup'.
CLAVICLE
ROTATORS
These
are pretty easy. Just create a rotator,
align it with the clavicle bone
(pivot-pivot and orientation), and
link the clavicle bone (each) to
its corresponding rotator. I named
mines Rotator_clavRT and Rotator_clavLT
(From now on, everytime I mention
node names, I'll just mention the
generic name. Add the RT or LT suffix
as supposed). Then, link both to
the last bone in the spine chain
(Bone_spine06). I made mines larger
and slightly deformed only to make
them easier to select.
HIPS
ROTATORS
Create
another rotator (I made mine slightly
bigger and colored in red), Align
it with the Rotator_spinelow (align
it both in position and orientation).
Link the little bones at the beginning
of the leg chains (the ones used for
skinning) to it.
THE
MASTER SPINE CONTROL
Now,
create a really big rotator, and align
it with the other two. We'll use this
one to drive the spine's rotations automatically.
The other ones will only be used to
fine-tune posing. Name it 'Torso Rotator_autocontrol'.
WIRING
THE SPINE UP
Allright.
Let's wire the spine up. Please
first verify that every rotator,
and all of the bones in the spine
chain, are correctly aligned. By
this, I mean that all of them must
have exactly the same local coords.
If one is misaligned, it might throw
off all of the others. Euler rotation
controllers (which are the ones
I use by default, with the occasional
Local Euler in some nodes) are parent-dependant,
so please check your alignments.
You can correct any misalignment,
by selecting the offending node,
going to the hierarchy panel, pivot
tab, turning on the 'Don't affect
children button', and aligining
the node. You can also use this
button to move bones to their proper
positions after creation. That said,
let's get on.
Select
all three spine rotators, and assign
list controllers to their rotation
tracks. Assign another euler rotation
controller to the 'available' tracks.
Name this new euler track something
like 'eulerXYZ_auto'. This way,
you'll know this controller is a
'driven' controller you can't touch.
Set as active the original Euler
tracks. Great. Now, select the huge
autocontrol rotator, go to the animation
menu (I use my quads for this),
and select 'Wire parameters-wire
parameter'. Select its X rotation
track. Drag to the first spine rotator,
click on it, and select its X rotation
track under the EulerXYZ_auto controller
(if you don't know how to wire parameters,
please refer to your max docs).
The wire parameters dialogue will
appear.
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On
one side, you'll see the tracks
for the autocontrol rotator, while
on the other you'll see the tracks
for the spine rotator object. In
both sides, the X Rotation track
should be selected already. Click
on the arrow going from the autocontrol
side to the spine rotator side (the
autocontrol will be the 'driver',
while the spine rotator will be
the 'driven', if you pardon me using
another 3d app's terminology). You'll
see an expression in the bottom
of the dialogue box. Leave it as
it is. Click the 'Connect' button.
That's it. Now, both nodes should
be connected. Without closing the
dialogue, select the autorotator
object and rotate it in X. The smaller
spine rotator should rotate with
it. Now, select both Y tracks, and
repeat the same operation. Same
for the Z tracks.
Once
done, close the transform track
for the spine rotator object. Navgate
down the hierarchy to the next rotator
object (this is a track-view like
window), open its transform tracks,
go to the second Euler controller
(EulerXYZ_auto), and select the
X track. Select the original X track
of the autocontrol object again.
Set again the autocontrol object
as 'driver', and the spine rotator
as 'driven'. Repeat wiring the corresponding
tracks of each object (X-X, Y-Y,
Z-Z). Repeat ell this with the third
rotator. You're done. If you like,
you can check the spine now. If
everything went ok, when you rotate
the autocontrol object in any axis,
the spine will bend with it, in
a realistci manner. This is what
this object is for. However, you
can go into the spine rotators and
rotate them to fine-tune the pose
(that's why we needed two euler
tracks. One for automatic rotation,
one for manual).
Now,
wasn't that easy?
The spine is all set up. It's the
only part that will be FK animated.
(the arms and legs use an IK/FK
approach).
Let's continue with the arms